Ardesia

Ardesia is an open source digital sketchpad software
to make colored free-hand annotations with digital ink
everywhere, record it and share on the network. This tool is easy to
use, fast and
quick to respond. You can draw upon the desktop or import
an image and annotate it and redistribute your work to the world.

The
tool facilitates the online presentations and demos showing in real
time your computer screen to anyone in the network.

Ardesia has been designed with the Glade/GtkBuilder tool
and it uses to draw the Cairo graphics library.